The present invention relates to assemblies for providing toggle or joystick control of computer keyboard keys.
Keyboards for desktop computers are generally provided with four keys that cause the cursor to move up, down, to the left or to the right on the monitor screen. While many programs do not involve a cursor, word processing, many games, and the writing or changing of software may require extensive movement of a cursor. In addition, many menu-driven programs require selecting one or more choices presented, and, on computers that are not equipped with a mouse or a trackball, the same keys that are used to move a cursor are used to make the selection.
Because the cursor control keys are so frequently used, most keyboards provide a dedicated cursor-control key pad, which is physically separate both from the main alpha section and from the numerical key pad, (which generally can be switched to also provide cursor control). In a large number of such keyboards the dedicated cursor control pad has four keys arranged in the form of an inverted "T". Three keys in a line on the bottom row of the pad effect lefthand, downward, and righthand cursor movement, respectively, and a single key centered on the top row causes upward cursor movement.
A cursor-control key pad with this layout is difficult to use without looking away from the screen or the main section of the keyboard in order to find the desired key, particularly because the "down" key is on the same row as the keys that control sideways motion. A number of devices have been conceived to make these and other cursor control keys easier to use without visual search. Generally, they provide a lever, or joystick, which can be moved to the right, say to depress the key that causes righthand cursor movement, and to the left, upward or downward to produce corresponding cursor movements.
These devices generally fall into two categories-those which mount over the keyboard and contain a fixed pivot for the joystick or handle, and those which rest freely on the keyboard over a central key and are rocked in different directions to depress the desired adjacent keys. The latter, while simple and cheap to produce, can be easily knocked off or removed and taken away. In addition, if used on an inverted "T" type key pad, they must be centered on the "down" key and cannot operate that key unless a different means, such as a depressable plunger in the handle is provided.
The great majority of such known devices use a fixed pivot and key engaging arms which are either attached to the handle or mounted separately and actuated by movement of the handle. Most incorporate a mounting plate which clips over the back and front ends of the keyboard housing or is otherwise screwed or adhered to the housing, often covering keys that are not actuated by the joystick. One known device is cemented to an "unused" center key. Many of these devices are structured so as to give very precise action and feel and, as a result, are quite complicated, cumbersome and expensive.